Thermally conductive polymer composition

ABSTRACT

A polymer composition that has an in-plane thermal conductivity of about 2.0 W/m-K or more is provided. The composition comprises 100 parts by weight of at least one aromatic polymer; from about 10 to about 50 parts by weight of an inorganic material having a hardness value of about 2.5 or more based on the Mohs hardness scale; and from about 20 to about 80 parts by weight of a thermally conductive particulate material having an average size of from about 1 to about 100 micrometers.

RELATED APPLICATIONS

The present application claims priority to U.S. Provisional ApplicationSer. No. 62/199,271, filed on Jul. 31, 2015, which is incorporatedherein in its entirety by reference thereto.

BACKGROUND OF THE INVENTION

Camera modules (or components) are often employed in mobile phones,laptop computers, digital cameras, digital video cameras, etc. Examplesinclude, for instance, compact camera modules that include a carriermounted to a base, digital camera shutter modules, components of digitalcameras, cameras in games, medical cameras, surveillance cameras, etc.Such camera modules have become more complex and now tend to includemore moving parts. In some cases, for example, two compact camera moduleassemblies can be mounted within a single module to improve picturequality (“dual camera” modules). In other cases, an array of compactcamera modules can be employed. Due to the increased complexity ofdifferent module designs, power consumption is increased, which in turnleads to an increase in the amount of heat that is produced by themodule. Unfortunately, the increased production of heat can be a problemdue to the fact that certain polymeric components in the camera modules(e.g., base, carrier, or cover) are not highly heat sensitive. Overtime,this can ultimately lead to a malfunction of the camera sensor.

As such, a need exists for a polymer composition that can be readilyemployed in the molded parts of camera modules.

SUMMARY OF THE INVENTION

In accordance with one embodiment of the present invention, a polymercomposition is disclosed that has an in-plane thermal conductivity ofabout 2.0 W/m-K or more. The composition comprises 100 parts by weightof at least one aromatic polymer; from about 10 to about 50 parts byweight of an inorganic material having a hardness value of about 2.5 ormore based on the Mohs hardness scale; and from about 20 to about 80parts by weight of a thermally conductive particulate material having anaverage size of from about 1 to about 100 micrometers.

Other features and aspects of the present invention are set forth ingreater detail below.

BRIEF DESCRIPTION OF THE FIGURES

A full and enabling disclosure of the present invention, including thebest mode thereof to one skilled in the art, is set forth moreparticularly in the remainder of the specification, including referenceto the accompanying figures, in which:

FIGS. 1-2 are perspective and front views of a compact camera module(“CCM”) that may be formed in accordance with one embodiment of thepresent invention.

DETAILED DESCRIPTION

It is to be understood by one of ordinary skill in the art that thepresent discussion is a description of exemplary embodiments only, andis not intended as limiting the broader aspects of the presentinvention.

Generally speaking, the present invention is directed to a thermallyconductive polymer composition that is capable of creating a thermalpathway for heat transfer away from a part so that “hot spots” can bequickly eliminated and the overall temperature of the part can belowered during use. More particularly, the thermally conductive polymercomposition has an in-plane thermal conductivity of about 2.0 W/m-K ormore, in some embodiments about 3.0 W/m-K or more, in some embodimentsabout 3.5 W/m-K or more, and in some embodiments, from about 3.5 toabout 10.0 W/m-K, as determined in accordance with ASTM E 1461-13. Thethermally conductive polymer composition may also have a through-planethermal conductivity of about 0.30 W/m-K or more, in some embodimentsabout 0.35 W/m-K or more, in some embodiments about 0.40 W/m-K or more,and in some embodiments, from about 0.50 to about 1.0 W/m-K, asdetermined in accordance with ASTM E 1461-13.

By selectively controlling the nature of the components employed andtheir relative concentration, the present inventors have discovered thatthe resulting polymer composition can achieve the desired degree ofthermal conductivity without adversely impacting the mechanicalproperties and surface quality of parts containing the composition. Forexample, the polymer composition contains a high-performance aromaticpolymer in combination with an inorganic filler material having ahardness value of about 2.5 or more, in some embodiments about 3.0 ormore, in some embodiments from about 3.0 to about 11.0, in someembodiments from about 3.5 to about 11.0, and in some embodiments, fromabout 4.5 to about 6.5 based on the Mohs hardness scale. Thermallyconductive particulate material is also employed in the polymercomposition. Such materials have an average size (e.g., diameter) ofabout 1 to about 100 micrometers, in some embodiments from about 10 toabout 90 micrometers, in some embodiments from about 20 to about 80micrometers, and in some embodiments, from about 30 to about 60micrometers, such as determined using laser diffraction techniques inaccordance with ISO 13320:2009 (e.g., with a Horiba LA-960 particle sizedistribution analyzer). The thermally conductive particulate materialmay also have a narrow size distribution. That is, at least about 70% byvolume of the particles, in some embodiments at least about 80% byvolume of the particles, and in some embodiments, at least about 90% byvolume of the particles may have a size within the ranges noted above.Without intending to be limited by theory, the present inventors havediscovered that the use of inorganic materials with a certain hardnessvalue and thermally conductive particulate materials with a certainsize, such as described above, can synergistically improve themechanical strength, adhesive strength, and surface smoothness of a partcontaining the composition. The resulting polymer composition may alsobe able to achieve less delamination of the polymer skin layer, whichenables it to be uniquely suited for very small parts.

The inorganic filler material is employed in the polymer composition inan amount of from about 10 to about 50 parts, in some embodiments fromabout 15 to about 45 parts, and in some embodiments, from about 20 toabout 40 parts by weight per 100 parts of the aromatic polymer.Likewise, the thermally conductive particulate material is employed inthe polymer composition in an amount of from about 20 to about 80 parts,in some embodiments from about 25 to about 75 parts, and in someembodiments, from about 30 to about 70 parts by weight per 100 parts ofthe aromatic polymer. For example, the inorganic filler materialtypically constitutes from about 20 wt. % to about 60 wt. %, in someembodiments from about 25 wt. % to about 55 wt. %, and in someembodiments, from about 30 wt. % to about 50 wt. % of the polymercomposition, while the thermally conductive particulate material mayconstitute from about 1 wt. % to about 50 wt. %, in some embodimentsfrom about 2 wt. % to about 40 wt. %, and in some embodiments, fromabout 5 wt. % to about 25 wt. % of the polymer composition

Various embodiments of the present invention will now be described inmore detail.

I. Aromatic Polymer

Aromatic polymers typically constitute from about 20 wt. % to about 70wt. %, in some embodiments from about 30 wt. % to about 60 wt. %, and insome embodiments, from about 35 wt. % to about 55 wt. % of the polymercomposition. The aromatic polymers are generally considered “highperformance” polymers in that they have a relatively high glasstransition temperature and/or high melting temperature depending on theparticular nature of the polymer. Such high performance polymers canthus provide a substantial degree of heat resistance to the resultingpolymer composition. For example, the aromatic polymer may have a glasstransition temperature of about 100° C. or more, in some embodimentsabout 120° C. or more, in some embodiments from about 140° C. to about350° C., and in some embodiments, from about 150° C. to about 320° C.The aromatic polymer may also have a melting temperature of about 200°C. or more, in some embodiments from about 220° C. to about 400° C., andin some embodiments, from about 240° C. to about 380° C. The glasstransition and melting temperatures may be determined as is well knownin the art using differential scanning calorimetry (“DSC”), such asdetermined by ISO Test No. 11357-2:2013 (glass transition) and11357-3:2011 (melting).

The aromatic polymer can be substantially amorphous, semi-crystalline,or crystalline in nature. One example of a suitable semi-crystallinearomatic polymer, for instance, is an aromatic polyamide. Particularlysuitable aromatic polyamides are those having a relatively high meltingtemperature, such as about 200° C. or more, in some embodiments about220° C. or more, and in some embodiments, from about 240° C. to about320° C., as determined using differential scanning calorimetry accordingto ISO Test No. 11357. The glass transition temperature of aromaticpolyamides is likewise generally from about 110° C. to about 160° C.

Aromatic polyamides typically contain repeating units held together byamide linkages (NH—CO) and are synthesized through the polycondensationof dicarboxylic acids (e.g., aromatic dicarboxylic acids), diamines(e.g., aliphatic diamines), etc. For example, the aromatic polyamide maycontain aromatic repeating units derived from an aromatic dicarboxylicacid, such as terephthalic acid, isophthalic acid,2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid,1,4-naphthalenedicarboxylic acid, 1,4-phenylenedioxy-diacetic acid,1,3-phenylenedioxy-diacetic acid, diphenic acid, 4,4′-oxydibenzoic acid,diphenylmethane-4,4′-dicarboxylic acid,diphenylsulfone-4,4′-dicarboxylic acid, 4,4′-biphenyldicarboxylic acid,etc., as well as combinations thereof. Terephthalic acid is particularlysuitable. Of course, it should also be understood that other types ofacid units may also be employed, such as aliphatic dicarboxylic acidunits, polyfunctional carboxylic acid units, etc. The aromatic polyamidemay also contain aliphatic repeating units derived from an aliphaticdiamine, which typically has from 4 to 14 carbon atoms. Examples of suchdiamines include linear aliphatic alkylenediamines, such as1,4-tetramethylenediamine, 1,6-hexanediamine, 1,7-heptanediamine,1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine,1,11-undecanediamine, 1,12-dodecanediamine, etc.; branched aliphaticalkylenediamines, such as 2-methyl-1,5-pentanediamine, 3-methyl-1,5pentanediamine, 2,2,4-trimethyl-1,6-hexanediamine,2,4,4-trimethyl-1,6-hexanediamine, 2,4-dimethyl-1,6-hexanediamine,2-methyl-1,8-octanediamine, 5-methyl-1,9-nonanediamine, etc.; as well ascombinations thereof. Repeating units derived from 1,9-nonanediamineand/or 2-methyl-1,8-octanediamine are particularly suitable. Of course,other diamine units may also be employed, such as alicyclic diamines,aromatic diamines, etc.

Particularly suitable polyamides may include poly(nonamethyleneterephthalamide) (PA9T), poly(nonamethyleneterephthalamide/nonamethylene decanediamide) (PA9T/910),poly(nonamethylene terephthalamide/nonamethylene dodecanediamide)(PA9T/912), poly(nonamethylene terephthalamide/11-aminoundecanamide)(PA9T/11), poly(nonamethylene terephthalamide/12-aminododecanamide)(PA9T/12), poly(decamethylene terephthalamide/11-aminoundecanamide)(PA10T/11), poly(decamethylene terephthalamide/12-aminododecanamide)(PA10T/12), poly(decamethylene terephthalamide/decamethylenedecanediamide) (PA10T/1010), poly(decamethyleneterephthalamide/decamethylene dodecanediamide) (PA10T/1012),poly(decamethylene terephlhalamide/tetramethylene hexanediamide)(PA10T/46), poly(decamethylene terephthalamide/caprolactam) (PA10T/6),poly(decamethylene terephthalamide/hexamethylene hexanediamide)(PA10T/66), poly(dodecamethylene lerephthalamide/dodecamelhylenedodecanediarnide) (PA12T/1212), poly(dodecamethyleneterephthalamide/caprolactam) (PA12T/6), poly(dodecamethyleneterephthalamide/hexamethylene hexanediamide) (PA12T/66), and so forth.Yet other examples of suitable aromatic polyamides are described in U.S.Pat. No. 8,324,307 to Harder, et al.

Another suitable semi-crystalline aromatic polymer that may be employedin the present invention is a polyaryletherketone. Polyaryletherketonesare semi-crystalline polymers with a relatively high meltingtemperature, such as from about 300° C. to about 400° C., in someembodiments from about 310° C. to about 390° C., and in someembodiments, from about 330° C. to about 380° C. The glass transitiontemperature may likewise be from about 110° C. to about 200° C.Particularly suitable polyaryletherketones are those that primarilyinclude phenyl moieties in conjunction with ketone and/or ethermoieties. Examples of such polymers include polyetheretherketone(“PEEK”), polyetherketone (“PEK”), polyetherketoneketone (“PEKK”),polyetherketoneetherketoneketone (“PEKEKK”), polyetheretherketoneketone(“PEEKK”),polyether-diphenyl-ether-ether-diphenyl-ether-phenyl-ketone-phenyl,etc., as well as blends and copolymers thereof.

As indicated above, substantially amorphous polymers may also beemployed in the polymer composition that lack a distinct melting pointtemperature. Suitable amorphous polymers may include, for instance,polyphenylene oxide (“PPO”), aromatic polycarbonates, aromaticpolyetherimides, etc. Aromatic polycarbonates, for instance, typicallyhave a glass transition temperature of from about 130° C. to about 160°C. and contain aromatic repeating units derived from one or morearomatic diols. Particularly suitable aromatic diols are bisphenols,such as gem-bisphenols in which two phenols groups are attached to asingle carbon atom of a bivalent connecting radical. Examples of suchbisphenols may include, for instance, such as4,4′-isopropylidenediphenol (“bisphenol A”), 4,4′-ethylidenediphenol,4,4′-(4-chloro-a-methylbenzylidene)diphenol,4,4′cyclohexylidenediphenol, 4,4 (cyclohexylmethylene)diphenol, etc., aswell as combinations thereof. The aromatic diol may be reacted with aphosgene. For example, the phosgene may be a carbonyl chloride havingthe formula C(O)Cl₂. An alternative route to the synthesis of anaromatic polycarbonate may involve the transesterification of thearomatic diol (e.g., bisphenol) with a diphenyl carbonate.

In addition to the polymers referenced above, crystalline polymers mayalso be employed in the polymer composition. Particularly suitable areliquid crystalline polymers, which have a high degree of crystallinitythat enables them to effectively fill the small spaces of a mold. Liquidcrystalline polymers are generally classified as “thermotropic” to theextent that they can possess a rod-like structure and exhibit acrystalline behavior in their molten state (e.g., thermotropic nematicstate). The polymers have a relatively high melting temperature, such asfrom about 250° C. to about 400° C., in some embodiments from about 280°C. to about 390° C., and in some embodiments, from about 300° C. toabout 380° C. Such polymers may be formed from one or more types ofrepeating units as is known in the art. A liquid crystalline polymermay, for example, contain one or more aromatic ester repeating units,typically in an amount of from about 60 mol. % to about 99.9 mol. %, insome embodiments from about 70 mol. % to about 99.5 mol. %, and in someembodiments, from about 80 mol. % to about 99 mol. % of the polymer. Thearomatic ester repeating units may be generally represented by thefollowing Formula (I):

wherein,

ring B is a substituted or unsubstituted 6-membered aryl group (e.g.,1,4-phenylene or 1,3-phenylene), a substituted or unsubstituted6-membered aryl group fused to a substituted or unsubstituted 5- or6-membered aryl group (e.g., 2,6-naphthalene), or a substituted orunsubstituted 6-membered aryl group linked to a substituted orunsubstituted 5- or 6-membered aryl group (e.g., 4,4-biphenylene); and

Y₁ and Y₂ are independently O, C(O), NH, C(O)HN, or NHC(O).

Typically, at least one of Y₁ and Y₂ are C(O). Examples of such aromaticester repeating units may include, for instance, aromatic dicarboxylicrepeating units (Y₁ and Y₂ in Formula I are C(O)), aromatichydroxycarboxylic repeating units (Y₁ is O and Y₂ is C(O) in Formula I),as well as various combinations thereof.

Aromatic dicarboxylic repeating units, for instance, may be employedthat are derived from aromatic dicarboxylic acids, such as terephthalicacid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, diphenylether-4,4′-dicarboxylic acid, 1,6-naphthalenedicarboxylic acid,2,7-naphthalenedicarboxylic acid, 4,4′-dicarboxybiphenyl,bis(4-carboxyphenyl)ether, bis(4-carboxyphenyl)butane,bis(4-carboxyphenyl)ethane, bis(3-carboxyphenyl)ether,bis(3-carboxyphenyl)ethane, etc., as well as alkyl, alkoxy, aryl andhalogen substituents thereof, and combinations thereof. Particularlysuitable aromatic dicarboxylic acids may include, for instance,terephthalic acid (“TA”), isophthalic acid (“IA”), and2,6-naphthalenedicarboxylic acid (“NDA”). When employed, repeating unitsderived from aromatic dicarboxylic acids (e.g., IA, TA, and/or NDA)typically constitute from about 5 mol. % to about 60 mol. %, in someembodiments from about 10 mol. % to about 55 mol. %, and in someembodiments, from about 15 mol. % to about 50% of the polymer.

Aromatic hydroxycarboxylic repeating units may also be employed that arederived from aromatic hydroxycarboxylic acids, such as, 4-hydroxybenzoicacid; 4-hydroxy-4′-biphenylcarboxylic acid; 2-hydroxy-6-naphthoic acid;2-hydroxy-5-naphthoic acid; 3-hydroxy-2-naphthoic acid;2-hydroxy-3-naphthoic acid; 4′-hydroxyphenyl-4-benzoic acid;3′-hydroxyphenyl-4-benzoic acid; 4′-hydroxyphenyl-3-benzoic acid, etc.,as well as alkyl, alkoxy, aryl and halogen substituents thereof, andcombination thereof. Particularly suitable aromatic hydroxycarboxylicacids are 4-hydroxybenzoic acid (“HBA”) and 6-hydroxy-2-naphthoic acid(“HNA”). When employed, repeating units derived from hydroxycarboxylicacids (e.g., HBA and/or HNA) typically constitute from about 10 mol. %to about 85 mol. %, in some embodiments from about 20 mol. % to about 80mol. %, and in some embodiments, from about 25 mol. % to about 75% ofthe polymer.

Other repeating units may also be employed in the polymer. In certainembodiments, for instance, repeating units may be employed that arederived from aromatic diols, such as hydroquinone, resorcinol,2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene,1,6-dihydroxynaphthalene, 4,4′-dihydroxybiphenyl (or 4,4′-biphenol),3,3′-dihydroxybiphenyl, 3,4′-dihydroxybiphenyl, 4,4′-dihydroxybiphenylether, bis(4-hydroxyphenyl)ethane, etc., as well as alkyl, alkoxy, aryland halogen substituents thereof, and combinations thereof. Particularlysuitable aromatic diols may include, for instance, hydroquinone (“HQ”)and 4,4′-biphenol (“BP”). When employed, repeating units derived fromaromatic diols (e.g., HQ and/or BP) typically constitute from about 1mol. % to about 30 mol. %, in some embodiments from about 2 mol. % toabout 25 mol. %, and in some embodiments, from about 5 mol. % to about20% of the polymer. Repeating units may also be employed, such as thosederived from aromatic amides (e.g., acetaminophen (“APAP”)) and/oraromatic amines (e.g., 4-aminophenol (“AP”), 3-aminophenol,1,4-phenylenediamine, 1,3-phenylenediamine, etc.). When employed,repeating units derived from aromatic amides (e.g., APAP) and/oraromatic amines (e.g., AP) typically constitute from about 0.1 mol. % toabout 20 mol. %, in some embodiments from about 0.5 mol. % to about 15mol. %, and in some embodiments, from about 1 mol. % to about 10% of thepolymer. It should also be understood that various other monomericrepeating units may be incorporated into the polymer. For instance, incertain embodiments, the polymer may contain one or more repeating unitsderived from non-aromatic monomers, such as aliphatic or cycloaliphatichydroxycarboxylic acids, dicarboxylic acids, diols, amides, amines, etc.Of course, in other embodiments, the polymer may be “wholly aromatic” inthat it lacks repeating units derived from non-aromatic (e.g., aliphaticor cycloaliphatic) monomers.

Although not necessarily required, the liquid crystalline polymer may bea “low naphthenic” polymer to the extent that it contains a minimalcontent of repeating units derived from naphthenic hydroxycarboxylicacids and naphthenic dicarboxylic acids, such asnaphthalene-2,6-dicarboxylic acid (“NDA”), 6-hydroxy-2-naphthoic acid(“HNA”), or combinations thereof. That is, the total amount of repeatingunits derived from naphthenic hydroxycarboxylic and/or dicarboxylicacids (e.g., NDA, HNA, or a combination of HNA and NDA) is typically nomore than 30 mol. %, in some embodiments no more than about 15 mol. %,in some embodiments no more than about 10 mol. %, in some embodiments nomore than about 8 mol. %, and in some embodiments, from 0 mol. % toabout 5 mol. % of the polymer (e.g., 0 mol. %). Despite the absence of ahigh level of conventional naphthenic acids, it is believed that theresulting “low naphthenic” polymers are still capable of exhibiting goodthermal and mechanical properties.

In one particular embodiment, the liquid crystalline polymer may beformed from repeating units derived from 4-hydroxybenzoic acid (“HBA”)and terephthalic acid (“TA”) and/or isophthalic acid (“IA”), as well asvarious other optional constituents. The repeating units derived from4-hydroxybenzoic acid (“HBA”) may constitute from about 10 mol. % toabout 80 mol. %, in some embodiments from about 30 mol. % to about 75mol. %, and in some embodiments, from about 45 mol. % to about 70% ofthe polymer. The repeating units derived from terephthalic acid (“TA”)and/or isophthalic acid (“IA”) may likewise constitute from about 5 mol.% to about 40 mol. %, in some embodiments from about 10 mol. % to about35 mol. %, and in some embodiments, from about 15 mol. % to about 35% ofthe polymer. Repeating units may also be employed that are derived from4,4′-biphenol (“BP”) and/or hydroquinone (“HQ”) in an amount from about1 mol. % to about 30 mol. %, in some embodiments from about 2 mol. % toabout 25 mol. %, and in some embodiments, from about 5 mol. % to about20% of the polymer. Other possible repeating units may include thosederived from 6-hydroxy-2-naphthoic acid (“HNA”),2,6-naphthalenedicarboxylic acid (“NDA”), and/or acetaminophen (“APAP”).In certain embodiments, for example, repeating units derived from HNA,NDA, and/or APAP may each constitute from about 1 mol. % to about 35mol. %, in some embodiments from about 2 mol. % to about 30 mol. %, andin some embodiments, from about 3 mol. % to about 25 mol. % whenemployed.

II. Inorganic Filler Material

As noted above, the inorganic filler material has a certain hardnessvalue for improving the properties of a part containing the polymercomposition. The nature of the material may vary, such as particles,fibers, etc. In certain embodiments, for instance, inorganic fillerparticles may be employed having a hardness value within the rangesnoted above. Examples of such particles may include, for instance,carbonates, such as calcium carbonate (CaCO₃, Mohs hardness of 3.0) or acopper carbonate hydroxide (Cu₂CO₃(OH)₂, Mohs hardness of 4.0);fluorides, such as calcium fluoride (CaFl₂, Mohs hardness of 4.0);phosphates, such as calcium pyrophosphate ((Ca₂P₂O₇, Mohs hardness of5.0), anhydrous dicalcium phosphate (CaHPO₄, Mohs hardness of 3.5), orhydrated aluminum phosphate (AlPO₄.2H₂O, Mohs hardness of 4.5);silicates, such as silica (SiO₂, Mohs hardness of 6.0), potassiumaluminum silicate (KAlSi₃O₈, Mohs hardness of 6), or copper silicate(CuSiO₃.H₂O, Mohs hardness of 5.0); borates, such as calciumborosilicate hydroxide (Ca₂B₅SiO₉(OH)₅, Mohs hardness of 3.5); alumina(AlO₂, Mohs hardness of 10.0); sulfates, such as calcium sulfate (CaSO₄,Mohs hardness of 3.5) or barium sulfate (BaSO₄, Mohs hardness of from 3to 3.5); and so forth, as well as combinations thereof. When employed,the inorganic particles typically have a median size (e.g., diameter) offrom about 0.1 to about 35 micrometers, in some embodiments from about 2to about 20 micrometers, in some embodiments from about 3 to about 15micrometers, and in some embodiments, from about 7 to about 12micrometers, such as determined using laser diffraction techniques inaccordance with ISO 13320:2009 (e.g., with a Horiba LA-960 particle sizedistribution analyzer). The filler inorganic particles may also have anarrow size distribution. That is, at least about 70% by volume of theparticles, in some embodiments at least about 80% by volume of theparticles, and in some embodiments, at least about 90% by volume of theparticles may have a size within the ranges noted above.

The inorganic filler material may also be fibers derived from a materialhaving the desired hardness value. Particularly suitable fibers for thispurpose include those derived from minerals, including silicates, suchas neosilicates, sorosilicates, inosilicates (e.g., calciuminosilicates, such as wollastonite; calcium magnesium inosilicates, suchas tremolite; calcium magnesium iron inosilicates, such as actinolite;magnesium iron inosilicates, such as anthophyllite; etc.),phyllosilicates (e.g., aluminum phyllosilicates, such as palygorskite),tectosilicates, etc.; sulfates, such as calcium sulfates (e.g.,dehydrated or anhydrous gypsum); mineral wools (e.g., rock or slagwool); and so forth. Particularly suitable are fibers derived frominosilicates, such as wollastonite (Mohs hardness of 4.5 to 5.0), whichare commercially available from Nyco Minerals under the tradedesignation NYGLOS® (e.g., NYGLOS® 4W or NYGLOS® 8).

The mineral fibers may have a median width (e.g., diameter) of fromabout 0.1 to about 35 micrometers, in some embodiments from about 2 toabout 20 micrometers, in some embodiments from about 3 to about 15micrometers, and in some embodiments, from about 7 to about 12micrometers, such as determined using laser diffraction techniques inaccordance with ISO 13320:2009 (e.g., with a Horiba LA-960 particle sizedistribution analyzer). The mineral fibers may also have a narrow sizedistribution. That is, at least about 70% by volume of the fibers, insome embodiments at least about 80% by volume of the fibers, and in someembodiments, at least about 90% by volume of the fibers may have a sizewithin the ranges noted above. The mineral fibers may also have anaspect ratio of from about 1 to about 50, in some embodiments from about2 to about 20, and in some embodiments, from about 4 to about 15. Thevolume average length of such mineral fibers may, for example, rangefrom about 1 to about 200 micrometers, in some embodiments from about 2to about 150 micrometers, in some embodiments from about 5 to about 100micrometers, and in some embodiments, from about 10 to about 50micrometers.

III. Thermally Conductive Particulate Material

The thermally conductive particulate material employed in the polymercomposition generally has a high specific surface area. The specificsurface area may be, for example, about 0.5 m²/g or more, in someembodiments about 1 m²/g or more, and in some embodiments, from about 2to about 40 m²/g. The specific surface area can be determined accordingto standard methods such as by the physical gas adsorption method(B.E.T. method) with nitrogen as the adsorption gas, as is generallyknown in the art and described by Brunauer, Emmet, and Teller (J. Amer.Chem. Soc., vol. 60, February, 1938, pp. 309-319). The particulatematerial may also have a powder tap density of from about 0.2 to about1.0 g/cm³, in some embodiments from about 0.3 to about 0.9 g/cm³, and insome embodiments, from about 0.4 to about 0.8 g/cm³, such as determinedin accordance with ASTM B527-15.

The thermally conductive particulate material also has a high intrinsicthermal conductivity, such as about 50 W/m-K or more, in someembodiments about 100 W/m-K or more, and in some embodiments, about 150W/m-K or more. Examples of such materials may include, for instance,boron nitride (BN), aluminum nitride (AlN), magnesium silicon nitride(MgSiN₂), graphite (e.g., expanded graphite), silicon carbide (SiC),carbon nanotubes, carbon black, metal oxides (e.g., zinc oxide,magnesium oxide, beryllium oxide, zirconium oxide, yttrium oxide, etc.),metallic powders (e.g., aluminum, copper, bronze, brass, etc.), etc., aswell as combinations thereof. Boron nitride is particularly suitable foruse in the polymer composition of the present invention. In fact, incertain embodiments, boron nitride may constitute a majority of thethermally conductive particulate material employed in the polymercomposition, such as about 50 wt. % or more, in some embodiments, about70 wt. % or more, and in some embodiments, from about 90 wt. % to 100wt. % of the thermally conductive particulate material. When employed,boron nitride is typically used in its hexagonal form to enhancestability and softness.

As noted above, the particulate material has an average size (e.g.,diameter) of about 1 to about 100 micrometers, in some embodiments fromabout 10 to about 90 micrometers, in some embodiments from about 20 toabout 80 micrometers, and in some embodiments, from about 30 to about 60micrometers. In certain embodiments, the thermally conductiveparticulate material may be in the form of individual platelets havingthe desired size. Nevertheless, the present inventors have discoveredthat agglomerates of the thermally conductive material having thedesired average size noted above tends to achieve a polymer compositionhaving better properties. Such agglomerates generally contain individualparticles that are aggregated together with no particular orientation orin a highly ordered fashion, for instance via weak chemical bonds suchas Van der Waals forces. Examples of suitable hexagonal boron nitrideagglomerates, for instance, include those commercially under thedesignations UHP-2 (Showa Denko) and PT-450 (Momentive PerformanceMaterials).

IV. Other Components

A wide variety of additional additives can also be included in thepolymer composition, such as electrically conductive fillers (e.g.,carbon fibers), particulate fillers (e.g., talc, mica, etc.), fibrousfillers (e.g., glass fibers), antimicrobials, pigments, antioxidants,stabilizers, surfactants, waxes, solid solvents, flame retardants,anti-drip additives, and other materials added to enhance properties andprocessability. Lubricants may also be employed in the polymercomposition that are capable of withstanding the processing conditionsof the liquid crystalline polymer without substantial decomposition.Examples of such lubricants include fatty acids esters, the saltsthereof, esters, fatty acid amides, organic phosphate esters, andhydrocarbon waxes of the type commonly used as lubricants in theprocessing of engineering plastic materials, including mixtures thereof.Suitable fatty acids typically have a backbone carbon chain of fromabout 12 to about 60 carbon atoms, such as myristic acid, palmitic acid,stearic acid, arachic acid, montanic acid, octadecinic acid, parinricacid, and so forth. Suitable esters include fatty acid esters, fattyalcohol esters, wax esters, glycerol esters, glycol esters and complexesters. Fatty acid amides include fatty primary amides, fatty secondaryamides, methylene and ethylene bisamides and alkanolamides such as, forexample, palmitic acid amide, stearic acid amide, oleic acid amide,N,N′-ethylenebisstearamide and so forth. Also suitable are the metalsalts of fatty acids such as calcium stearate, zinc stearate, magnesiumstearate, and so forth; hydrocarbon waxes, including paraffin waxes,polyolefin and oxidized polyolefin waxes, and microcrystalline waxes.Particularly suitable lubricants are acids, salts, or amides of stearicacid, such as pentaerythritol tetrastearate, calcium stearate, orN,N′-ethylenebisstearamide. When employed, the lubricant(s) typicallyconstitute from about 0.05 wt. % to about 1.5 wt. %, and in someembodiments, from about 0.1 wt. % to about 0.5 wt. % (by weight) of thepolymer composition.

In other embodiments, a fibrous filler (e.g., glass fibers) can beemployed in the polymer composition to help further improve strength.For example, glass fibers may constitute from about 2 wt. % to about 40wt. %, in some embodiments from about 5 wt. % to about 35 wt. %, and insome embodiments, from about 6 wt. % to about 30 wt. % of the polymercomposition. Suitable glass fibers includes those formed from E-glass,A-glass, C-glass, D-glass, AR-glass, R-glass, S1-glass, S2-glass, etc.,as well as mixtures thereof. The median width of the glass fibers mayfrom about 0.1 to about 35 micrometers, in some embodiments from about 2to about 20 micrometers, and in some embodiments, from about 3 to about10 micrometers. The volume average length of the glass fibers may alsobe from about 10 to about 500 micrometers, in some embodiments fromabout 100 to about 400 micrometers, in some embodiments from about 150to about 350 micrometers, and in some embodiments, from about 200 toabout 325 micrometers. The glass fibers may also have a relatively highaspect ratio (average length divided by nominal diameter), such as fromabout 1 to about 100, in some embodiments from about 10 to about 60, andin some embodiments, from about 30 to about 50.

V. Formation

The aromatic polymer, inorganic filler material, thermally conductiveparticulate material, and other optional additives may be melt processedor blended together. The components may be supplied separately or incombination to an extruder that includes at least one screw rotatablymounted and received within a barrel (e.g., cylindrical barrel) and maydefine a feed section and a melting section located downstream from thefeed section along the length of the screw. The extruder may be a singlescrew or twin screw extruder. If desired, the inorganic filler materialand thermally conductive particulate material can be added to theextruder a location downstream from the point at which the aromaticpolymer is supplied. The speed of the screw may be selected to achievethe desired residence time, shear rate, melt processing temperature,etc. For example, the screw speed may range from about 50 to about 800revolutions per minute (“rpm”), in some embodiments from about 70 toabout 150 rpm, and in some embodiments, from about 80 to about 120 rpm.The apparent shear rate during melt blending may also range from about100 seconds⁻¹ to about 10,000 seconds⁻¹, in some embodiments from about500 seconds⁻¹ to about 5000 seconds⁻¹, and in some embodiments, fromabout 800 seconds⁻¹ to about 1200 seconds⁻¹. The apparent shear rate isequal to 4Q/πR³, where Q is the volumetric flow rate (“m³/s”) of thepolymer melt and R is the radius (“m”) of the capillary (e.g., extruderdie) through which the melted polymer flows.

Regardless of the particular manner in which it is formed, the presentinventors have discovered that the resulting polymer composition canpossess excellent thermal properties. For example, the melt viscosity ofthe polymer composition may be low enough so that it can readily flowinto the cavity of a mold having small dimensions. In one particularembodiment, the polymer composition may have a melt viscosity of fromabout 1 to about 200 Pa-s, in some embodiments from about 5 to about 180Pa-s, in some embodiments from about 10 to about 150 Pa-s, and in someembodiments, from about 60 to about 120 Pa-s, determined at a shear rateof 1000 seconds⁻¹. Melt viscosity may be determined in accordance withISO Test No. 11443:2005 at a temperature that is 15° C. higher than themelting temperature of the composition (e.g., 350° C.).

VI. Applications

Once formed, the polymer composition may be molded into a shaped partfor use in a wide variety of different applications. For example, theshaped part may be molded using a one-component injection moldingprocess in which dried and preheated plastic granules are injected intothe mold. Regardless of the technique employed, it has been discoveredthat the molded part of the present invention may have a relativelysmooth surface, which may be represented by its surface glossiness). Forexample, the surface glossiness as determined using a gloss meter at anangle of from about 80° to about 85° may be about 35% or more, in someembodiments about 38% or more, and in some embodiments, from about 40%to about 60%. Conventionally, it was believed that parts having such asmooth surface would not also possess sufficiently good mechanicalproperties. Contrary to conventional thought, however, the molded partof the present invention has been found to possess excellent mechanicalproperties. For example, the part may possess a high weld strength,which is useful when forming the thin part of a camera module. Forexample, the part may exhibit a weld strength of from about 10kilopascals (“kPa”) to about 100 kPa, in some embodiments from about 20kPa to about 80 kPa, and in some embodiments, from about 40 kPa to about70 kPa, which is the peak stress as determined in accordance with ISOTest No. 527-1:2012 (technically equivalent to ASTM D638-14) at 23° C.

The part may also possess a Charpy notched impact strength of about 2kJ/m² or more, in some embodiments about 3 kJ/m² or more, and in someembodiments, from about 4 to about 40 kJ/m², measured at 23° C.according to ISO Test No. 179-1:2010) (technically equivalent to ASTMD256-10, Method B). The tensile and flexural mechanical properties arealso good. For example, the part may exhibit a tensile strength of fromabout 20 to about 500 MPa, in some embodiments from about 50 to about400 MPa, and in some embodiments, from about 60 to about 350 MPa; atensile break strain of about 0.5% or more, in some embodiments fromabout 0.6% to about 10%, and in some embodiments, from about 0.8% toabout 3.5%; and/or a tensile modulus of from about 5,000 MPa to about20,000 MPa, in some embodiments from about 8,000 MPa to about 20,000MPa, and in some embodiments, from about 9,000 MPa to about 15,000 MPa.The tensile properties may be determined in accordance with ISO Test No.527:2012 (technically equivalent to ASTM D638-14) at 23° C. The part mayalso exhibit a flexural strength of from about 20 to about 500 MPa, insome embodiments from about 50 to about 400 MPa, and in someembodiments, from about 80 to about 350 MPa; a flexural break strain ofabout 0.5% or more, in some embodiments from about 0.6% to about 10%,and in some embodiments, from about 0.8% to about 3.5%; and/or aflexural modulus of from about 5,000 MPa to about 20,000 MPa, in someembodiments from about 8,000 MPa to about 20,000 MPa, and in someembodiments, from about 9,000 MPa to about 15,000 MPa. The flexuralproperties may be determined in accordance with ISO Test No. 178:2010(technically equivalent to ASTM D790-10) at 23° C. The molded part mayalso exhibit a deflection temperature under load (DTUL) of about 200° C.or more, and in some embodiments, from about 200° C. to about 280° C.,as measured according to ASTM D648-07 (technically equivalent to ISOTest No. 75-2:2013) at a specified load of 1.8 MPa. The Rockwellhardness of the part may also be about 40 more, some embodiments about50 or more, and in some embodiments, from about 60 to about 100, asdetermined in accordance with ASTM D785-08 (Scale M).

The polymer composition and/or shaped molded part can be used in avariety of applications. For example, the molded part can be employed inlighting assemblies, battery systems, sensors and electronic components,portable electronic devices such as smart phones, MP3 players, mobilephones, computers, televisions, automotive parts, etc. In one particularembodiment, the molded part may be employed in a camera module, such asthose commonly employed in wireless communication devices (e.g.,cellular telephone). For example, the camera module may employ a base,carrier assembly mounted on the base, a cover mounted on the carrierassembly, etc. The base may have a thickness of about 500 micrometers orless, in some embodiments from about 10 to about 450 micrometers, and insome embodiments, from about 20 to about 400 micrometers. Likewise, thecarrier assembly may have a wall thickness of about 500 micrometers orless, in some embodiments from about 10 to about 450 micrometers, and insome embodiments, from about 20 to about 400 micrometers.

One particularly suitable camera module is shown in FIGS. 1-2. As shown,a camera module 500 contains a carrier assembly 504 that overlies a base506. The base 506, in turn, overlies an optional main board 508. Due totheir relatively thin nature, the base 506 and/or main board 508 areparticularly suited to be molded from the polymer composition of thepresent invention as described above. The carrier assembly 504 may haveany of a variety of configurations as is known in the art. In oneembodiment, for example, the carrier assembly 504 may contain a hollowbarrel that houses one or more lenses 604, which are in communicationwith an image sensor 602 positioned on the main board 508 and controlledby a circuit 601. The barrel may have any of a variety of shapes, suchas rectangular, cylindrical, etc. In certain embodiments, the barrel maybe formed from the polymer composition of the present invention and havea wall thickness within the ranges noted above. It should be understoodthat other parts of the camera module may also be formed from thepolymer composition of the present invention. For example, as shown, acover may overly the carrier assembly 504 that includes, for example, asubstrate 510 (e.g., film) and/or thermal insulating cap 502. In someembodiments, the substrate 510 and/or cap 502 may also be formed fromthe polymer composition.

The present invention may be better understood with reference to thefollowing examples.

Test Methods

Melt Viscosity:

The melt viscosity (Pa-s) may be determined in accordance with ISO TestNo. 11443:2005 at a shear rate of 1000 s⁻¹ and temperature 15° C. abovethe melting temperature (e.g., 350° C.) using a Dynisco LCR7001capillary rheometer. The rheometer orifice (die) had a diameter of 1 mm,length of 20 mm, L/D ratio of 20.1, and an entrance angle of 180°. Thediameter of the barrel was 9.55 mm+0.005 mm and the length of the rodwas 233.4 mm.

Melting Temperature:

The melting temperature (“Tm”) may be determined by differentialscanning calorimetry (“DSC”) as is known in the art. The meltingtemperature is the differential scanning calorimetry (DSC) peak melttemperature as determined by ISO Test No. 11357-2:2013. Under the DSCprocedure, samples were heated and cooled at 20° C. per minute as statedin ISO Standard 10350 using DSC measurements conducted on a TA Q2000Instrument.

Deflection Temperature Under Load (“DTUL”):

The deflection under load temperature may be determined in accordancewith ISO Test No. 75-2:2013 (technically equivalent to ASTM D648-07).More particularly, a test strip sample having a length of 80 mm,thickness of 10 mm, and width of 4 mm may be subjected to an edgewisethree-point bending test in which the specified load (maximum outerfibers stress) was 1.8 Megapascals. The specimen may be lowered into asilicone oil bath where the temperature is raised at 2° C. per minuteuntil it deflects 0.25 mm (0.32 mm for ISO Test No. 75-2:2013).

Tensile Modulus, Tensile Stress, and Tensile Elongation:

Tensile properties may be tested according to ISO Test No. 527:2012(technically equivalent to ASTM D638-14). Modulus and strengthmeasurements may be made on the same test strip sample having a lengthof 80 mm, thickness of 10 mm, and width of 4 mm. The testing temperaturemay be 23° C., and the testing speeds may be 1 or 5 mm/min.

Flexural Modulus, Flexural Stress, and Flexural Strain:

Flexural properties may be tested according to ISO Test No. 178:2010(technically equivalent to ASTM D790-10). This test may be performed ona 64 mm support span. Tests may be run on the center portions of uncutISO 3167 multi-purpose bars. The testing temperature may be 23° C. andthe testing speed may be 2 mm/min.

Notched Charpy Impact Strength:

Notched Charpy properties may be tested according to ISO Test No. ISO179-1:2010) (technically equivalent to ASTM D256-10, Method B). Thistest may be run using a Type A notch (0.25 mm base radius) and Type 1specimen size (length of 80 mm, width of 10 mm, and thickness of 4 mm).Specimens may be cut from the center of a multi-purpose bar using asingle tooth milling machine. The testing temperature may be 23° C.

Rockwell Hardness:

Rockwell hardness is a measure of the indentation resistance of amaterial and may be determined in accordance with ASTM D785-08 (ScaleM). Testing is performed by first forcing a steel ball indentor into thesurface of a material using a specified minor load. The load is thenincreased to a specified major load and decreased back to the originalminor load. The Rockwell hardness is a measure of the net increase indepth of the indentor, and is calculated by subtracting the penetrationdivided by the scale division from 130.

Thermal Conductivity:

In-plane and through-plane thermal conductivity values are determined inaccordance with ASTM E1461-13.

EXAMPLE

Samples 1-5 are formed from various percentages of a liquid crystallinepolymer, calcium pyrophosphate, lubricant (Glycolube™ P), boron nitride,and black color masterbatch, as indicated in Table 1 below. The blackcolor masterbatch contains 80 wt. % liquid crystalline polymer and 20wt. % carbon black. The boron nitride (Polartherm™ PT450, Momentive) hasa mean particle size of from 30 to 50 micrometers, a specific surfacearea of from 1 to 7 m²/g, and a tap density of 0.35 g/cm³. The liquidcrystalline polymer in each of the samples is formed from HBA, HNA, TA,BP, and APAP, such as described in U.S. Pat. No. 5,508,374 to Lee et al.Compounding is performed using an 18-mm single screw extruder. Parts areinjection molded the samples into plaques (60 mm×60 mm).

TABLE 1 Sample 1 2 3 4 5 LCP 47.20 47.20 47.20 47.20 47.20 Lubricant0.30 0.30 0.30 0.30 0.30 Black Color Masterbatch 12.50 12.50 12.50 12.5012.50 Calcium Pyrophosphate 40.00 20.00 20.00 10.00 10.00 Boron Nitride— 20.00 0 30.00 0 Zinc Oxide — 0 20.00 0 30.00

The molded parts are also tested for thermal and mechanical properties.The results are set forth below in Table 2.

TABLE 2 Sample 1 2 3 4 5 MV1000 (Pa-s) 52 93 62 98 68 MV400 (Pa-s) 67134 100 145 172 Melt Temp (° C.) (1^(st) Heat) 330 333 332 334 331 DTUL@ 1.8 Mpa (° C.) 218 212 178 217 175 Charpy Notched (kJ/m²) 4 5 1 4 1Rockwell Hardness (M-scale) 64 33 61 28 63 Tensile Strength (MPa) 103 7042 61 34 Tensile Modulus (MPa) 9,111 9,445 6,273 9,996 5,827 TensileElongation (%) 3.8 2.0 0.9 1.2 0.7 Flexural Strength (MPa) 125 101 57 9754 Flexural Modulus (MPa) 9,135 10,509 6,036 11,625 5,677 FlexuralElongation (%) >3.5 2.3 1.1 2.0 1.1 Thermal Conductivity (W/m-K), inplane 1.2 3.3 1.4 4.6 1.5 Thermal Conductivity (W/m-K), through plane0.35 0.46 0.46 0.49 0.49 Thermal Conductivity (W/m-K), in plane, FLO 1.33.9 1.2 5.4 1.3 Thermal Conductivity (W/m-K), through plane, FLO 0.5 0.90.7 0.9 0.8

These and other modifications and variations of the present inventionmay be practiced by those of ordinary skill in the art, withoutdeparting from the spirit and scope of the present invention. Inaddition, it should be understood that aspects of the variousembodiments may be interchanged both in whole or in part. Furthermore,those of ordinary skill in the art will appreciate that the foregoingdescription is by way of example only, and is not intended to limit theinvention so further described in such appended claims.

What is claimed is:
 1. A polymer composition having an in-plane thermalconductivity of about 2.0 W/m-K or more, wherein the compositioncomprises: 100 parts by weight of at least one aromatic liquidcrystalline polyester; from about 10 to about 50 parts by weight of aninorganic material having a hardness value of about 2.5 or more based onthe Mohs hardness scale; and from about 20 to about 80 parts by weightof a thermally conductive particulate material having an average size offrom about 1 to about 100 micrometers.
 2. The polymer composition ofclaim 1, wherein about 70% by volume or more of the thermally conductiveparticulate material has an average size of from about 1 to about 100micrometers.
 3. The polymer composition of claim 1, wherein liquidcrystalline polyesters constitute from about 20 wt. % to about 70 wt. %of the polymer composition.
 4. The polymer composition of claim 1,wherein the liquid crystalline polyester has a glass transitiontemperature of about 100° C. or more and/or a melting temperature ofabout 200° C. or more.
 5. The polymer composition of claim 1, whereinthe liquid crystalline polyester contains repeating units derived fromterephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid,4-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, hydroquinone,4,4′-biphenol, acetaminophen, or a combination thereof.
 6. The polymercomposition of claim 1, wherein the inorganic material is in the form ofparticles.
 7. The polymer composition of claim 6, wherein the inorganicmaterial includes calcium pyrophosphate, calcium sulfate, bariumsulfate, or a combination thereof.
 8. The polymer composition of claim6, wherein the particles of the inorganic material have a median size offrom about 0.1 to about 35 micrometers.
 9. The polymer composition ofclaim 1, wherein the inorganic material is in the form of mineralfibers.
 10. The polymer composition of claim 9, wherein the mineralfibers are derived from wollastonite.
 11. The polymer composition ofclaim 9, wherein the mineral fibers have a median width of from about0.1 to about 35 micrometers.
 12. The polymer composition of claim 1,wherein the inorganic filler material constitutes from about 20 wt. % toabout 60 wt. % of the polymer composition and the thermally conductiveparticulate material constitutes from about 1 wt. % to about 50 wt. % ofthe polymer composition.
 13. The polymer composition of claim 1, whereinthe thermally conductive particulate material has a specific surfacearea of about 0.5 m²/g or more.
 14. The polymer composition of claim 1,wherein the thermally conductive particulate material has a powder tapdensity of from about 0.2 to about 1.0 g/cm³.
 15. The polymercomposition of claim 1, wherein the thermally conductive particulatematerial has an intrinsic thermal conductivity of about 50 W/m-K ormore.
 16. The polymer composition of claim 1, wherein the thermallyconductive particulate material includes boron nitride.
 17. The polymercomposition of claim 16, wherein boron nitride constitutes about 50 wt.% or more of the thermally conductive particulate material in thepolymer composition.
 18. The polymer composition of claim 1, wherein thepolymer composition has a through-plane thermal conductivity of about0.30 W/m-K or more.
 19. A shaped part comprising the polymer compositionof claim
 1. 20. A camera module comprising the shaped part of claim 19.21. The camera module of claim 20, wherein the camera module comprises agenerally planar base on which is mounted a carrier assembly, whereinthe base, carrier assembly, or both contain the molded part.